SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00c4c7aaf85346d642117eec0b18ee8b1bd1bbfeedc80c69d52ac34300d36fd4' 
  AND token = 'vwS3E2mD2hrEN3VsOteLABvScjYy+2XJWvzSUWcDcN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}